Isolation member and isolation member seat for fracturing subsurface geologic formations

ABSTRACT

An embodiment of an assembly includes an isolation member and an isolation member seat to together isolate a first portion of a well casing from a second portion of the well casing. The isolation member comprises an exterior surface including at least one of a ceramic material, metallic glass, a reactive metal or a PGA material, and the isolation member includes an interior chamber to receive an explosive device. The explosive device may be surrounded by a non-compressible fluid, and may include a pressure sensor, a processor, a battery and an explosive charge. The ceramic, metallic glass and reactive metal and may comprise one of zirconium oxide, aluminum oxide, Bulk metallic Glass, silicon nitride, tungsten carbide, reactive metal alloy or PGA salt. The isolation member is resistant to deformation within an isolation member seat under the application of a substantial pressure differential across the isolation member and isolation member seat. Detonation of the isolation member prevents the isolation member from presenting an obstruction to subsequent well operations.

STATEMENT OF RELATED APPLICATIONS

This application is a continuation-in-part depending from and claiming priority to U.S. Non-Provisional application Ser. No. 14/741,182 filed On Jun. 16, 2015, which is a continuation-in-part application depending and claiming priority to U.S. Non-Provisional application Ser. No. 14/521,662 filed on Oct. 23, 2014 which, in turn, claims priority to U.S. Provisional Application No. 61/898,088 filed on Oct. 31, 2013.

BACKGROUND

1. Field of the Invention

The present invention relates to an improved sacrificial isolation plug and plug seat for use in fluidically isolating a targeted geologic zone for hydraulic fracturing operations to enhance production of hydrocarbons from a well drilled into the targeted geologic zone.

2. Background of the Related Art

Hydraulic fracturing is the fracturing of rock by a pressurized liquid. Some hydraulic fractures form naturally. Induced hydraulic fracturing or hydro-fracturing, commonly known as “fracing,” is a technique in which a fluid, typically water, is mixed with a proppant and chemicals to form a mixture that is injected at high pressure into a well to create small fractures in a hydrocarbon-bearing geologic formation along which the hydrocarbon fluids such as gas, oil or condensate may migrate to the well for production to the surface. Hydraulic pressure is removed from the well, then small grains of the proppant, for example, sand or aluminum oxide, hold the fractures open once the formation pressure achieves an equilibrium. The technique is commonly used in wells for shale gas, tight gas, tight oil, coal seam gas and hard rock wells. This well stimulation technique is generally only conducted once in the life of the well and greatly enhances fluid removal rates and well productivity.

A hydraulic fracture is formed by pumping fracturing fluid into the well at a rate sufficient to increase pressure downhole at the target zone (determined by the location of the well casing perforations) to exceed that of the fracture gradient (pressure gradient) of the rock. The fracture gradient is defined as the pressure increase per unit of the depth due to its density and it is usually measured in pounds per square inch per foot or bars per meter. The rock cracks and the fracture fluid continues further into the rock, extending the crack still further, and so on. Fractures are localized because pressure drop off with frictional loss attributed to the distance from the well. Operators typically try to maintain “fracture width,” or slow its decline, following treatment by introducing into the injected fluid a proppant—a material such as grains of sand, ceramic beads or other particulates that prevent the fractures from closing when the injection is stopped and the pressure of the fluid is removed. The propped fracture is permeable enough to allow the flow of formation fluids to the well. Formation fluids include gas, oil, water and fluids introduced to the formation during completion of the well during fracturing.

The location of one or more fractures along the length of the borehole is strictly controlled by various methods that create or seal off holes in the casing of the well. A well may be fraced in stages by setting an isolation member seat below the geologic formation to be fraced to isolate one or more lower zones open to the well from the anticipated pressure to be later applied to a zone closer to the surface.

Hydraulic-fracturing equipment used in oil and natural gas fields usually consists of a slurry blender, one or more high-pressure, high-volume fracturing pumps (typically powerful triplex or quintuplex pumps) and a monitoring unit. Associated equipment includes fracturing tanks, one or more units for storage and handling of proppant, high-pressure treating iron, a chemical additive unit (used to accurately monitor chemical addition), low-pressure flexible hoses, and many gauges and meters for flow rate, fluid density, and treating pressure. Chemical additives are typically 0.5% percent of the total fluid volume. Fracturing equipment operates over a range of pressures and injection rates, and can reach up to 100 megapascals (15,000 psi) and 265 litres per second (9.4 cu ft/s) (100 barrels per minute).

A problem that can be encountered in a fracing operation involves the impairment to subsequent operations that can result from the presence of a common frack plug. After the fracing operation is concluded, the surface pressure is restored to a pressure at which the well will flow and produce formation fluids to the surface for recovery. A fracing plug having a sufficiently low density can be floated or back-flowed from the well, but a plug having a low density may be deformed by the large pressure differential applied across the plug and plug seat and thereby compromised during fracturing operations. Most of the time, a phenolic or composite plug gets lodged in the seat and cannot be flowed to the surface. This unwanted obstruction has to be removed from the well to prevent impairment of subsequent well operations. This obstruction also prevents oil from flowing to the surface.

A workover operation can be implemented in which a drilling instrument is introduced into the well to drill out and mechanically destroy the plug, but a workover operation requires that a workover rig be brought to the surface end of the well for downhole operations. The need for the rental, transportation and use of a rig imposes substantial delays, substantial costs and the added risk of a well blow-out.

What is needed is a fracing plug that has as sufficient density and resistance to deformation so that it can be used in conjunction with a seat to reliably isolate geologic formation zones below the plug seat from anticipated fracturing pressures applied to geologic formation zones above the plug seat and that does not impair subsequent well operations. What is needed is a fracing plug that can be manipulated to engage and seal after it is seated at the targeted interval of a well casing. What is needed is a fracing plug that can be run into a well and set at the targeted interval of the well casing, and that will not present a well obstacle to the flow of fluid after the fracing operation is completed.

BRIEF SUMMARY

One embodiment of the apparatus of the present invention provides an isolation member and a corresponding isolation member seat. The isolation member sealably engages the isolation member seat after the isolation member seat is secured at the targeted depth in the well casing. The isolation member is secured to the isolation member seat in an unseated condition, and the isolation member can be selectively engaged with the isolation member seat to enable fracing operations by manipulation of the direction and rate of flow of fluid within the well casing at the isolation member seat.

One embodiment of the apparatus of the present invention provides an isolation member such as, for example, a plug of a predetermined diameter is shaped for sealing engagement with a corresponding isolation member seat which, in the case of a plug, is a plug seat. In one embodiment, the isolation member, such as a plug, is captured within a cage connected to the isolation member seat. These components together provide a selectively activatable check valve that can be run into a well and secured within the well casing at a targeted depth prior to activation. The isolation member captured within the cage connected to the isolation member seat assembly may be introduced into the well at the surface and pumped or run on a wireline downhole for being secured within the casing. Activation of the apparatus is obtained by pumping fluid into the well at the surface to induce fluid to flow downwardly through the cage and through the isolation member seat. The force imparted by the fluid flow urges the isolation member captured within the cage into sealing engagement with the isolation member seat.

One embodiment of the apparatus of the present invention provides an isolation member secured in an unseated position to the isolation member seat using a mechanical fuse element. The mechanical fuse element may position the isolation member proximal to, but disengaged with, the corresponding sealing portion of the isolation member seat.

It will be understood that these arrangements, the caged isolation member and the isolation member secured in an unseated position using one or more mechanical fuse elements, allow well fluids to flow around the isolation member seat as the isolation member seat and the isolation member secured thereto, either by mechanical fuse element or using a cage, or both, is run into the well and positioned at the targeted depth, and for the movement of the isolation member into engagement with the corresponding isolation member seat upon pressurization of the wellhead and the casing above the isolation member seat to induce a fluid flow downwardly into the isolation member seat. For example, for the embodiment of the apparatus comprising an isolation member captured in a cage connected to the isolation member seat, the isolation member is moved from a disengaged position within the cage to a sealing position by the flow of fluid in a downwardly direction to engage and seal the isolation member with the isolation member seat that is exposed to the cage. As another example, for the embodiment of the apparatus comprising an isolation member secured in an unseated position to the isolation member seat by one or more mechanical fuse elements, a downwardly flow of fluids in the well at a sufficient rate will dislodge the isolation member from the unseated position when the force applied to the isolation member by the movement of well fluids exceeds a threshold amount of force needed to cause the one or more mechanical fuse elements to sacrificially fail and thereby release the isolation member from the unseated position to engage and seal with the isolation member seat. It will be understood that the amount of force imparted to the unseated isolation member is a function of several factors including, but not limited to, the rate of flow of well fluids downwardly against the isolation member, the size of the isolation member, the size of the well casing in which the isolation member seat is secured, and the density of the well fluids. It will be further understood that the flow area between the isolation member, secured in an unseated position by the one or more mechanical fuse elements, and the isolation member seat, is another factor that affects the flow rate required to compromise the mechanical fuse element(s) to release the isolation member to engage and seal with the isolation member seat.

One embodiment of the apparatus of the present invention provides an isolation member, either caged or secured in an unseated position using one or more mechanical fuses, for sealing with an isolation member seat and the isolation member contains an explosive charge for fragmenting the isolation member after use. The isolation member is constructed in a manner that provides sufficient resistance to deformation of the isolation member as a large pressure differential is applied across the seated isolation member and the engaged isolation member seat. The explosive charge can be disposed within the isolation member and activated by a pressure sensor that senses when the pressure in the well is above a predetermined threshold. The pressure sensor then generates a signal to a processor that will not enable the explosive charge until the pressure sensor senses a substantially decreased pressure far below the pressure at which the well is fractured. In this manner, the processor and pressure sensor will not enable the explosive charge to detonate until after the pressure sensor has detected both an elevated pressure, indicative of hydraulic fracturing of the formation adjacent to the open perforations above the depth at which the isolation member seat is secured in the well casing, and a subsequent low pressure, indicative of the hydraulic fracturing of the for motion having been completed.

One embodiment of the present invention provides an isolation member such as, for example, a plug, that can be fragmented by detonation of an explosive charge within an interior chamber of the plug to produce a plurality of plug fragments that do not interfere with subsequent well operations. In one embodiment, the use of a ceramic, metallic glass, reactive metal or PGA (polyglycolic acid) salt body provides sufficient resistance to plug deformation under large pressure differentials across the plug and seat applied during fracing operations. In addition, these materials can provide for favorable fragmentation of the plug upon detonation of the explosive charge stored within an interior chamber of the plug to prevent unwanted obstacles having a substantial size obstructing flow in the well.

In one embodiment of the isolation member of the present invention, a battery, a pressure sensor and a circuit are included within an interior chamber along with the explosive charge. The pressure sensor is disposed in fluid communication with an exterior surface of the isolation member through an aperture in the ceramic outer structure of the isolation member, which may be in the form of a plug. The pressure sensor detects a predetermined pressure threshold and initiates a predetermined delay period prior to detonation. Upon elapse of the predetermined delay period, a circuit is completed that generates a high voltage electrical current from the battery to the explosive charge to detonate the explosive charge and thereby fragment the isolation member. It will be understood that the fragmentation of the plug dramatically increases the surface area that is exposed to the fluids in the well. As with the case with a dissolvable frack plug, a much more rapid rate of dissolution of the fragments is obtained as a result of the dramatically increased surface area at which dissolution may occur.

The higher fracing pressures achievable by use of embodiments of the isolation member of the present invention increase the success and effectiveness of the fracing process, lowers or eliminates workover rig rental costs, and prevents unwanted delays after the fracing process.

In one embodiment of the apparatus of the present invention, a mechanical fuse element such as, for example, a shear pin or a rupture ring is installed between the isolation member and the isolation member seat will secure the isolation member in an unseated position relative to the isolation member seat in order to keep the seat open and to allow well fluids to flow from beneath the seat and through the seat, and around the isolation member secured in the unseated position off of, but near the seat, to enable the isolation member and the isolation member seat combination into the well casing to the targeted interval for installation. The mechanical fuse element may be adapted to fail and to release the isolation member from its unseated position to engage and seal with the isolation member.

In one embodiment of the apparatus of the present invention, the isolation member, the isolation member seat and one of the cage or the mechanical fuse element that secures the isolation member to the isolation member seat can be run into a well casing along with a perforating gun disposed above the apparatus. The perforating gun can be used to perforate the well casing above the targeted interval in which the isolation member and the isolation member seat are to be activated by a downward flow of well fluids across the isolation member and the isolation member seat. It will be understood that in the event that the perforating gun does not discharge properly and must be removed from the well, the isolation member will remain in the unseated position while the perforating gun is removed, re-tooled or repaired, or while another perforating gun is run into the well casing and positioned above the isolation member and isolation member seat. After perforation is complete, the fracing pressure will shear the pin causing the isolation member to sealably engage the isolation member seat to isolate the portion of the well casing below the isolation member seat from the perforations above the isolation member seat, which are open to an adjacent geologic formation to be fractured.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a sectional view of a well drilled into the earth's crust and illustrating a series of hydraulic fractures disposed at a predetermined spacing to enhance production and recovery of formation fluids from a hydraulically fractured subsurface geologic formation.

FIG. 2 is the sectional view of the well of FIG. 1 illustrating the lack of fractures within the targeted geologic formation prior to the creation of the hydraulic fractures and illustrating a location of a desired placement of a plug and a seat isolate zones deeper in the well than the plug/seat (to the right) from zones shallower in the well than the plug/seat (to the left).

FIG. 3 is a sectional elevation of an embodiment of a plug-shaped isolation member received in a partially-caged isolation member seat set within the casing of the drilled well illustrated in FIG. 2 with the isolation member secured in an unseated position relative to the isolation member seat.

FIG. 4 is a disassembled view of the isolation member of FIG. 3.

FIG. 5 is a sectional view of an embodiment of a plug-shaped isolation member.

FIG. 6 is an embodiment of an assembly of the present invention including an isolation member, and a cage connected to an isolation member seat secured within a well casing to isolate a first portion of the well casing from a second portion of the well casing upon activation to engage the isolation member with the isolation member seat.

DETAILED DESCRIPTION

One embodiment of the present invention provides a plug-shaped isolation member having an outer surface with a frusto-conical portion of sufficient smoothness to enable the frusto-conical sealing portion of the plug-shaped isolation member to engage and to seal with an isolation member seat having a sealing surface conforming to at least a portion of the frusto-conical portion of the isolation member seat, wherein the plug-shaped isolation member seat has substantial resistance to deformation by an applied pressure differential across the seal created by the plug-shaped isolation member received within the isolation member seat. The embodiment of the plug-shaped isolation member contains an explosive device that can be detonated to destroy the isolation member from within and to thereby fragment the isolation member into a large plurality of small fragments. The embodiment of the plug-shaped isolation member may include a hollow interior of the isolation member, along with the explosive device, wherein a filler material comprises a non-compressible fluid like an oil.

The manner in which an embodiment of the isolation member of the present invention is made may vary, but will generally include the steps of providing a ceramic, metallic glass, reactive metal or PGA outer shell having a hollow interior and, optionally, a hole through which a pressure sensor may be inserted into the isolation member. An embodiment of an isolation member of the present invention may include an explosive device and a filler material that can be disposed within the hollow interior. In one embodiment of the isolation member, a first upper portion and a second lower portion are secured together to form an isolation member that seals with the isolation member seat along a tapered portion of the isolation member.

In one embodiment, a ceramic, metallic glass, reactive metal or PGA isolation member may consist of two or more pieces secured together to form a body. In another embodiment, the isolation member consists of a unitary body having a hole for insertion of a pressure sensor to enable the explosive charge and the timer-controlled detonator.

In one embodiment, the isolation member may comprise one of zirconium oxide, silicon nitride, tungsten carbide, zirconia toughened alumina, Bulk Metallic Glass (BMG), aluminum oxide, reactive metal or polyglycolic acid (“PGA”). The high compressive strengths of these materials enable the isolation member to seat in the isolation member seat and to seal together to isolate deeper well zones from shallower well zones to be fraced. This requires the isolation member and isolation member seat to withstand a very high fracing pressure on an uphole side of the isolation member and isolation member seat and a substantially lower pressure on a downhole side of the isolation member and isolation member seat. Embodiments of the ceramic, metallic glass, reactive metal or PGA fracing plug of the present invention may be manufactured by, for example, but not by way of limitation, isostatic pressing, hot isostatic processing, (HIP), injection molding, slip casting, or other casting techniques. It is possible that an isolation member comprising zirconia or BMG with a thin wall thickness of 0.250″ can be cast and subsequently hot isostatically pressed to increase the flexural strength of the isolation member so it can withstand very high differential pressures, yet have less material to interfere with fracing other zones when the plug is fragmented by detonation of the explosive device.

FIG. 1 is a sectional view of a well 20 drilled from the surface 21 into the earth's crust 29 and illustrating a series of hydraulic fractures 26 disposed at a predetermined spacing 28 to enhance production and recovery of formation fluids from a hydraulically fractured subsurface geologic formation 24. The drilled well 20 may include multiple layers of surface casing as is known in the art. The drilled well 20 may include one or more turns or changes in direction to align the portion of the well 20 to be perforated or otherwise to gather fluids within a known geological structure, seam or formation 24. The fractures 26 created in the formation 24 are generally disposed at a predetermined spacing 28 selected for optimal drainage. The targeted formation 24 may reside between a top layer 22 and an underlying layer 23 within the earth's crust 29. It will be understood that fluids entering the well 20 flow according to a pressure gradient in the direction of the arrow 27 to the surface for processing, storage or transportation.

FIG. 2 is the sectional view of the well 20 of FIG. 1 illustrating the lack of fractures 26 (seen in FIG. 1) within the targeted geologic formation 24 prior to the creation of the hydraulic fractures shown in FIG. 1. FIG. 2 illustrates, using a circle, a location of a desired placement of a plug (not shown) and a seat (not shown to receive the plug to thereby isolate a zone 50, that is deeper in the well than the plug seat (i.e., to the right) from a zone 51 that is shallower in the well 20 than the plug seat (i.e. to the left). It will be understood that the plug and plug seat are to be placed in a portion of the casing 62 that lies within the targeted geologic formation 24 and that the pressure at any given location within the well 20 is approximately equal to the pressure at a wellhead 49 at the surface 21 plus the product of the vertical elevation change 46 times the density (as measured in units corresponding to the unit used to measure depth) of a fluid residing in the well 20, assuming that the well 20 is tilled with the fluid.

FIG. 3 is a sectional elevation of an embodiment of a plug-shaped isolation member 10 of the present invention secured in an unseated position relative to an isolation member seat 44 that has been set within a section of a casing 62 of the drilled well 20 (not shown in FIG. 3) illustrated in FIG. 2 to create an isolating seal. It will be understood that a number of tools exist for setting the isolation member seat 44 within the portion of the casing 62 in which the seal is to be affected, and that those tools and the methods of setting those tools are not within the scope of the present invention. FIG. 3 is provided merely to illustrate the manner in which an embodiment of an isolation member 10 moves through the bore 70 of the casing 62 to engage the isolation member seat 44 after the seat 44 is set in the portion of the casing 62 with the isolation member 10 secured in an unseated position relative to the isolation member seat 44. The isolation member 10 and the isolation member seat 44 do not form a seal to isolate a lower portion of the bore 71 from the upper portion of the bore 70 that is uphole to the isolation member 10 and isolation member seat 44 as long as the isolation member 10 remains in the unseated position relative to the isolation member seat 44 shown in FIG. 3. The isolation member 10 is secured in the unseated position shown in FIG. 3 by one or more mechanical fuse elements 81 disposed intermediate the isolation member 10 and the isolation member seat 44. The unseated position causes an open flow passage 92, which surrounds the tapered portion 13 of the plug-shaped isolation member 10 shown in FIG. 3. FIG. 3 further shows a pair of optional inwardly disposed retainer members 91 coupled to the isolation member seat 44 to ensure that the isolation member 10 does not become separated from the isolation member seat 44 if the mechanical fuse elements 81 were to fail prematurely. It will be understood that the isolation member 44 may, in one embodiment, be introduced into the unseated position illustrated in FIG. 3 prior to the connection or installation of the inwardly-disposed retainer members 91 on the isolation member seat 44. It will be further understood that the open flow passage 92 may be larger or smaller than that shown in FIG. 3 which is for illustration purposes only. The isolation member seat 44 with the isolation member 10 secured in the unseated position shown in FIG. 3 can be run into the well casing 62 because fluid can easily pass through the open flow passage 92 between the isolation member 10 and the isolation member seat 44.

FIG. 4 is an exploded view of an embodiment of a plug-shaped isolation member 10 of the present invention. The isolation member 10 of FIG. 4 comprises a hollow interior consisting of a hollow interior 15 of an upper portion 11 and a hollow interior 16 of a lower portion 12. Securing of the upper portion 11 to the lower portion 12 provides a plug-shaped isolation member 10 having an exterior surface consisting of the exterior surface 17 of the first hemispherical portion 11 and the exterior surface 18 of the lower portion 12. Returning to FIG. 3, the sealing surface 85 of the lower portion 12 of the isolation member 10 can be fluoropolymer coated to prevent the isolation member 10 from wedging and getting stuck in the isolation member seat 44. Optionally, the sealing surface 84 of the isolation member seat 44 can also be fluoropolymer coated. Optionally, both the sealing surface 84 of the isolation member seat 44 and the sealing surface 85 of the isolation member 10 may both be fluoropolymer coated.

FIG. 5 is a plan view of a hollow interior 15 of the upper portion 11 of FIG. 4. An aperture 30 in the upper portion 11 of the may be fluidically connected by a conduit 31 to a pressure sensor 32. The pressure sensor 32 closes a switch 33 upon sensing a predetermined threshold pressure through the aperture 30.

Upon receiving the signal from the pressure sensor 32, a timer is activated. After a predetermined time, a signal will be sent to a detonator to detonate the explosive charge to fragment the isolation member 10. Upon detonation of the explosive charge 36, the outer shell of the plug 10 is fragmented.

FIG. 6 is an embodiment of an assembly of the present invention including an isolation member 10, an isolation member seat 44 secured within a well casing 62 to isolate a first portion 70 of the well casing 62 from a second portion 71 of the well casing 62 upon activation to engage the isolation member 10 with the isolation member seat 44. The isolation member 10 of the assembly of FIG. 6 is captured within a cage 87 through which well fluids (not shown) may flow without separating the isolation member 10 from the isolation member seat 44 to which the cage 87 is attached. It will be understood that the isolation member 10 is of the same type as discussed above, that is, it includes an interior chamber to receive components that will enable the isolation member 10 to be fragmented by an explosive charge after use in effecting a seal within the well casing 62.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components and/or groups, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

The corresponding structures, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 

What is claimed is:
 1. An assembly, including an isolation member and an isolation member seat, for securing in a tubular string within a well in the earth's crust to isolate a pressure within a first portion of the well from a pressure in a second portion of the well, the assembly comprising: an isolation member having an interior chamber and an exterior surface, including at least one of ceramic, metallic glass, reactive metal or polyclycolic acid, the isolation member including an exterior sealing surface; an isolation member seat adapted for being secured in a well casing and having a sealing surface that is shaped to receive and to sealably engage with the exterior sealing surface of the isolation member; at least one mechanical fuse element disposed intermediate the isolation member seat and the isolation member to secure the isolation member in an unseated position relative to the isolation member seat, the mechanical fuse element securing the isolation member in an unseated position with an open flow passage intermediate the sealing surface of the isolation member and the sealing surface of the isolation member seat; a battery received within the interior chamber of the isolation member; an explosive charge of an explosive material received within the interior chamber of the isolation member and conductively coupled to the battery; a pressure sensor received within the interior chamber of the isolation member in fluid communication with an aperture extending from the exterior surface to the interior chamber; and a processor received within the interior chamber and conductively coupled to receive an electrical current from the battery, conductively coupled to receive a signal from the pressure sensor, and conductively coupled to generate, after a predetermined time interval, a detonating current to detonate the explosive device in response to detecting a predetermined pressure sensed using the pressure sensor; wherein after the isolation member seat is adapted for being secured within the well casing; wherein the sealing surface on the isolation member and the sealing surface on the isolation member seat can sealably engage one with the other upon release of the isolation member from the unseated position resulting from the application of force to the isolation member and the one or more mechanical fuse elements due to a downward flow of well fluids at a rate sufficient to cause the one or more mechanical fuse elements to fail and release the isolation member; and wherein detonation of the explosive charge fragments the isolation member to limit the size of debris in the well that may obstruct subsequent well operations and to increase a cumulative surface area of the isolation member to promote accelerated dissolution of a plurality of fragments.
 2. The assembly of claim 1, further comprising: one or more retainer members connected to the isolation member seat and positioned to prevent separation of the isolation member from the isolation member seat in the event of premature failure of the one or more mechanical fuse elements.
 3. The assembly of claim 1, wherein the explosive charge is formed with a recess to receive at least a portion of the battery; and wherein the recess in the explosive charge is shaped to prevent battery shielding of a portion of the isolation member upon detonation of the explosive charge.
 4. The assembly of claim 1, wherein the isolation member includes a plurality of separate portions coupled together form the isolation member.
 5. The isolation member of claim 1, wherein the exterior surface of the isolation member is comprised of at least one of a ceramic material, metallic glass, a reactive metal or polyclycolic acid.
 6. An assembly, including an isolation member and an isolation member seat, for securing in a tubular string within a well in the earth's crust to isolate a pressure within first portion of the well from a pressure in a second portion of the well, the assembly comprising: an isolation member having an interior chamber and an exterior surface, including at least one of ceramic, metallic glass, reactive metal or polyglycolic acid, the isolation member including an exterior sealing surface; an isolation member seat adapted for being secured in a well casing and having a sealing surface that is shaped to receive and to sealably engage with the exterior sealing surface of the isolation member; a cage connected to the isolation member seat to secure the isolation member within a space within the cage and to prevent unwanted separation between the isolation member and the isolation member seat; a battery received within the interior chamber of the isolation member; an explosive charge of an explosive material received within the interior chamber of the isolation member and conductively coupled to the battery; a pressure sensor received within the interior chamber of the isolation member in fluid communication with an aperture extending from the exterior surface to the interior chamber; and a processor received within the interior chamber and conductively coupled to receive an electrical current from the battery, conductively coupled to receive a signal from the pressure sensor, and conductively coupled to generate, after a predetermined time interval, a detonating current to detonate the explosive device in response to detecting a predetermined pressure sensed using the pressure sensor; wherein after the isolation member seat is adapted for being secured within the well casing; wherein the sealing surface on the isolation member and the sealing surface on the isolation member seat can sealably engage one with the other upon movement of the isolation member from the unseated position within the cage by the application of a force to the isolation member by a downward flow of well fluids at a rate sufficient to cause the isolation member to move downwardly within the cage and engage the isolation member seat; and wherein detonation of the explosive charge fragments the isolation member to limit the size of debris in the well that may obstruct subsequent well operations and to increase a cumulative surface area of the isolation member to promote accelerated dissolution of a plurality of fragments.
 7. The assembly of claim 6, wherein the assembly further includes at least one mechanical fuse element disposed intermediate the isolation member seat and at least one of the cage and the isolation member to secure the isolation member in an unseated position relative to the isolation member seat, the mechanical fuse element securing the isolation member in an unseated position within the cage with an open flow passage intermediate the sealing surface of the isolation member and the sealing surface of the isolation member seat. 